Reorganised content based on feedback and IA proposal in
https://etherpad.openstack.org/p/osa-install-guide-IA:
1. Move affinity content to the appendix
2. Move security hardening configuration to the appendix
3. Create an advanced configuration section in the appendix
4. Delete configuring hosts and configuring target host networking information,
and create a configuration file examples section
5. Move glance configuration information to the developer docs
6. Move overridding configuration defaults to the appendix.
7. Move checking configuration file content to the installation chapter
Change-Id: I71efaf2472b1233f1b1a1367fcb00ca598d27ea9
Implements: blueprint osa-install-guide-overhaul
5cc9d0b004